Light Bridge Brightening and Plasma Ejection Driven by a Magnetic Flux Emergence Event

Abstract

Abstract Observations with the Goode Solar Telescope (GST) are presented here showing that the emergence of 1.91 × 1018 Mx of new magnetic flux occurred at the edge of a filamentary light bridge (LB). This emergence was accompanied by brightness enhancement of a photospheric overturning convection cell (OCC) at the endpoints of the emerging magnetic structure. We present an analysis of the origin and the dynamics of this event using high-resolution GST Fe i 1564.85 nm vector magnetic field data, TiO photospheric, and Hα chromospheric images. The emerged structure was 1.5 × 0.3 Mm in size at the peak of development and lasted for 17 minutes. Doppler observations showed presence of systematic upflows before the appearance of the magnetic field signal and downflows during the decay phase. Changes in the orientation of the associated transverse fields, determined from the differential angle, suggest the emergence of a twisted magnetic structure. A fan-shaped jet was observed to be spatially and temporally correlated with the endpoint of the OCC intruding into the LB. Our data suggest that the emerging fields may have reconnected with the magnetic fields in the vicinity of the LB, which could lead to the formation of the jet. Our observation is the first report of flux emergence within a granular LB with evidence in the evolution of vector magnetic field, as well as photosphere convection motions, and supports the idea that the impulsive jets above the LB are caused by magnetic reconnection.